It all started on Sunday Morning April 22 at 7:51am PDT, when several people located in the Northern California and Reno areas reported seeing a bright fireball visible in daylight.

The American Meteor Society compiled a list of 121 visual observations on their web site, an impressive number for a full sunlight meteor. Several observers in Nevada also mentioned having heard a sonic boom, implying that the meteoroid was large enough to penetrate the lower part of Earth’s atmosphere.

Bill Cooke of the Meteoroid Environments Office at NASA’s Marshall Space Flight Center in Huntsville, Ala., estimates the object was about 3-4 m, weighed in at around 70 metric tons and at the time of disintegration released energy equivalent to a 4-kiloton explosion. (reported in NASA-JPL press release).

Lisa Warren snapped three quick photos of a meteor streaking across the sky above Reno on Sunday morning, April 22. The meteor created a sonic boom heard over hundreds of miles from the Reno-Tahoe area to Southern California.

This event interested my office neighbor at the SETI Institute, Peter Jenniskens, an expert in meteor showers who also retrieved the fragments of 2008TC3 in Sudan in 2008. He pointed out that the size of the Californian meteor is very similar to 2008TC3, hence fragments should have reached the surface. Getting fresh fragments of meteoroids, called meteorites, is key for astronomers to understand the composition of those remnants of the formation of the solar system. Fresh fragments are unaltered by the Earth’s weather and erosion processes, so they are pristine samples which can be used to detect organic materials for instance.

On Tuesday several scientists from the Bay Area met at NASA Ames to discuss a strategy for a search campaign. An examination of the radar data map by Marc Fries revealed that dozens of fragments from 100g to 1 kg range may have reached the surface in an area NW of Placerville, in the Gold country.

Radar map by Marc Fries showing the possible location of fragments (green area) of the meteor between Auburn and Placerville.

Yesterday, Tuesday April 24, Peter Jenniskens and Mike Koop drove to the site of the radar map. The possible presence of fragments was already spreading quickly and an email was posted on the meteorite-list mailing list announcing that Robert Ward found the first piece at 11am.

Sean T. MurrayTue, 24 Apr 2012 13:33:22 -0700It is an honor to announce that, at 11:00 am local, Robert Ward was thefirst to recover a stone from the April 22, 2012, California fireball —which was evidently generated by a large, carbonaceous CM mass. Robert isnow responsible for the initial recovery of two-out-of-three-ever Californiawitnessed falls, including Red Canyon Lake.

A second fragment was discovered shortly later by Peter Jenniskens himself. It appears to be a CM Chondrite meteorite, one of the rarer types of meteorites, rich in a mix of complex organic compounds like amino-acids. They graciously sent me this picture taken at the time of the discovery of the, now called, Sutter’s Mill meteorite.

Unfortunately a storm is reaching California and the rain may alter the remaining fragments. If you are not too far and feel like looking for meteorites, you should definitely check out the area for meteorites. They are easily discernible thanks to their dark color.

Another plea for help, if you have access to security camera footage taken on Sunday morning, it may be useful to check them to see if the fireball was visible. Astronomers could use them to pin down the site of the fall, maximizing the hunt for fragments.

Clear skies & good hunting,

Franck M.

Added at 11am:

From Marc Fries: A third stone was found by a gent from Sacramento. He went up there and walked around on the roads, and found it on a gravel road. http://briencook.com/lotus/

Dr. Franck Marchis is a Senior Scientist and Science Outreach Manager at the SETI Institute and Chief Scientific Officer at Unistellar. Marchis earned his PhD in Astrophysics at the Université Paul Sabatier, France, in 2000. He is a planetary astronomer with 22 years of experience in academic, international and non-profit scientific institutions and has conducted multiple research projects in a wide range of areas. He is best known for his discovery and characterization of multiple asteroids, his study of Io volcanism and imaging of exoplanets, planets around other stars. In April 2007, the asteroid numbered 1989SO8 was named “(6639) Marchis” in honor of his work in the field of multiple asteroids.
More recently, he has been also involved in the definition of new generation of AOs for 8 -10 m class telescopes and future Extremely Large Telescopes. He has developed algorithms to process and enhance the quality of images, both astronomical and biological.
His currently involved in the Gemini Planet Imager Exoplanet Survey, which consists in imaging exoplanets using an extreme AO system for the Gemini South telescope. This new instrument is capable of imaging and recording spectra of young Jupiter-like exoplanets orbiting around nearby stars.

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There are already more than three meteorites from this fall when one combines those mentioned here and those in this article that shows two specimen found by Ward and two more without a backstory and looking differently. Hmm …

[…] perhaps best known for retrieving the fragments of asteroid 2008 TC3 which fell in Sudan in 2008. Astronomer Franck Marchis wrote in his Cosmic Diary blog that Jenniskens realized the size of the California meteor was very similar to 2008 TC3, and so […]

[…] perhaps best known for retrieving the fragments of asteroid 2008 TC3 which fell in Sudan in 2008. Astronomer Franck Marchis wrote in his Cosmic Diary blog that Jenniskens realized the size of the California meteor was very similar to 2008 TC3, and so […]

Sorry but I don’t buy this at all. El Dorado county is hundreds of square miles in size and the area northwest of Placerville is sparsely populated, mountainous and densely brush covered. The odds against even one fragment being found ever are astronomical let alone 3 with in days. I call BS.

This is why they are starting the search in the most obvious places. The most obvious place is under the weather radar map of the meteor and to check the local roads and trails. It would obviously be much hard to find a piece hidden in tall weeds or the bushes.

I live right near the area and Sunday morning while sitting in my house drinking my coffee I heard what I thought at the time was an airplane flying over, but now I know it was the meteor. I am going to looks for bits of it around my house. Amazing!

[…] perhaps best known for retrieving the fragments of asteroid 2008 TC3 which fell in Sudan in 2008. Astronomer Franck Marchis wrote in his Cosmic Diary blog that Jenniskens realized the size of the California meteor was very similar to 2008 TC3, and so […]

[…] perhaps best known for retrieving the fragments of asteroid 2008 TC3 which fell in Sudan in 2008. Astronomer Franck Marchis wrote in his Cosmic Diary blog that Jenniskens realized the size of the California meteor was very similar to 2008 TC3, and so […]

[…] perhaps best known for retrieving the fragments of asteroid 2008 TC3 which fell in Sudan in 2008. Astronomer Franck Marchis wrote in his Cosmic Diary blog that Jenniskens realized the size of the California meteor was very similar to 2008 TC3, and so […]